1. Field of the Invention
This invention relates to a disc cartridge, and more particularly to a disc cartridge in which a disc medium such as an optical disc, a photo-magnetic disc, a magnetic disc, a floppy disc or the like is rotatably received.
2. Description of the Prior Art
In general, a disc cartridge such as a tray system or a cartridge system using a casing has been conventionally employed for protecting a floppy disc, a compact disc, a video disc or the like which is used for a digital-data storing unit, a video unit or the like from damage and dust to ensure its safety.
For this purpose, the conventional disc cartridge, as shown in FIG. 1, is provided with a slidable shutter 100 which is adapted to close a pickup inserting hole 102 of a rectangular shape and/or a drive pin inserting hole of a casing 104 in nonuse and open the holes in use.
Unfortunately, in the conventional disc cartridge, in order to properly position a pickup of a disc cartridge operating unit such as a recording and/or reproducing unit (hereinafter referred to as "cartridge operating unit") on a disc 110 by operating the shutter to open the pickup inserting hole 102 to insert it through the hole 102 into the casing 104, the pickup is required to be first horizontally moved and then downwardly moved, because the casing 104 and shutter 100 are provided with front end walls 106 and 108, respectively. Thus, the conventional disc cartridge causes movement of the pickup to be complicated, resulting in not only proper positioning of the pickup on the disc being highly difficult to achieve but free or desired layout of the pickup being prevented. Also, this causes a pickup moving area or an area in which the pickup can move with respect to the casing to be substantially reduced, so that it is required to substantially enlarge the casing as compared with a size of the disc in order to enlarge the pickup moving area to a degree sufficient to permit the pickup to carry out a satisfactory operation with respect to an outermost section of the disc.
Accordingly, it would be highly desirable to develop a disc cartridge which is capable of enlarging a pickup moving area to a degree sufficient to permit a pickup of a cartridge operating unit to be smoothly inserted into a casing by simple movement and operate a disc over a wide area, ensuring desired layout of the pickup, as well as being compact and readily assembled to lead to a significant improvement in productivity of the cartridge.